<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>

<div id="app"> 
  <h2>总价格：{{totalPrice}}</h2>
</div>
  
<script src="../js/vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',//用于挂载要管理的元素
    data: {
      books: [
        {id: 110, name: 'Unix编程艺术', price: 119},
        {id: 111, name: '代码大全', price: 105},
        {id: 112, name: '深入计算机原理', price: 98},
        {id: 113, name: '现代操作系统', price: 87}
      ]
    },
    computed: {
      totalPrice: function () {
        let result = 0
        for (let i=0; i < this.books.length; i++) {
          result += this.books[i].price
        }
        return result

        // for (let i in this.books) {
        //   this.books[i]
        // }

        // for (let book of this.books) {

        // }
      }
    }
  })
</script>

</body>
</html>